The invention relates to modified polyurethanes (PU) based on polyurethane reactive systems composed of organic polyisocyanates and polyol formulations, which additionally contain polymer modifiers and fillers, to a process for their preparation, and to their use in electroplating or metallization.
The production of polyurethane molded bodies has long been known (e.g. from Polyurethane Kunststoffhandbuch 7, Carl Hanser Verlag Munich-Vienna 1983).
In DE-A 4 110 976, polyisocyanates modified with so-called polymer modifiers are used for the production of PU molded bodies.
The plastics provided with electrodeposited metal layers have hitherto been acrylonitrile-butadiene-styrene copolymers (ABS) (Ullmann's Encyclopedia of Industrial Chemistry). Moldings are produced from the mentioned ABS copolymers by the thermoplastic injection molding process and are subsequently coated with a metal surface by electroplating processes. Such coated moldings are used in the sanitary field, for example as fittings, handles and towel-rails, or in the automotive sector, for example as decorative elements (lettering, Mercedes star) and radiator grills, etc. Although polyurethane molded bodies are also coated in that manner, the adhesion of the metal layer to the PU (polyurethane) is very poor (Metallisieren von Kunststoffgehausen unter EMV-, Umwelt-und Recyclingaspekten, 1st edition 1998, by Prof. Dr.-Ing. Ernst Habinger, Dr.-Ing. Autor Singh Sidhu, Leuze-Verlag).
DE-A 195 17 338 describes the production of a composite product which is molded from plastics and is provided with a selective metal coating. The product is composed of at least two parts made from different polymers, one part being a coatable plastics material and a second part being a non-coatable plastics material. The second part is molded over the first part in a manner such that an area of the first part is not covered. A metal coating is then applied to the uncovered area of the first part. Polyurethane is mentioned as a non-coatable plastics material, while an ABS/PC plastics material is described as a coatable plastics material.